Definitions

Up Day: stock closes equal or higher than previous day's close
Down Day: stock closes lower than previous day's close

Examples:

To screen for stocks where the Up Days volume is greater than 50% of the total volume during the last 20 bars enter the following rule:

UpDownRatio(20,0) > 0.50

To screen for stocks with greater UpDownRatio in the last 10 bars compared to the previous 10 bars enter the following rule:

UpDownRatio(10,0) > UpDownRatio(10,10)